ThreadSendSignal (Function)

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Synchronizing threads

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ThreadSendSignal (Function)

In french: ThreadEnvoieSignal

The current thread sends an event to the specified thread in order to unlock it. This function simplifies the synchronization between threads without having to implement an advanced management of events.

Reminder:

A thread is a process run in parallel with the current application (main thread). This allows you to run a task in the background (e.g. backup, etc.).
ThreadWaitSignal and ThreadSendSignal are used to synchronize the threads two by two.

Example

See additional examples

// Création d'un signal
EventCreate("Allez-y", eventManual, eventClose)
// Exécution d'un premier thread
ThreadExecute("Thread1", threadNormal, "Thread_Premier")
// Bloque le thread en cours jusqu'à l'obtention du signal
ThreadWaitSignal()

// Exécution d'un second thread
ThreadExecute("Thread2", threadNormal, "Thread_Second")
// Bloque le thread en cours jusqu'à l'obtention du signal
ThreadWaitSignal()

// Modifie le signal pour exécuter les threads
EventChange("Allez-y", eventOpen)

//----------------------------------------------
PROCEDURE Thread_Premier()
Trace(dbgInfo(dbgProcess) + " - ThreadEnvoieSignal(threadPrincipal)")
ThreadSendSignal(threadMain)
EventWait("Allez-y")
Trace(dbgInfo(dbgProcess) + " - Signal reçu")

//--------------------------------------------
PROCEDURE Thread_Second()
Trace(dbgInfo(dbgProcess) + " - ThreadEnvoieSignal(threadPrincipal)")
ThreadSendSignal(threadMain)
EventWait("Allez-y")
Trace(dbgInfo(dbgProcess) + " - Signal reçu")

Syntax

Sending a signal to a thread identified by its name Hide the details

ThreadSendSignal(<Thread name>)

<Thread name>: Character string

Name of the thread to which the event must be sent. To send an event to the main thread, use the character string "." or the threadMain constant.
No event can be sent to the current thread.
This name is given when running the thread (ThreadExecute).

Sending a signal to a thread identified by a Thread variable Hide the details

ThreadSendSignal(<Thread>)

<Thread>: Thread variable

Name of the Thread variable corresponding to the thread to which the signal must be sent. To send an event to the main thread, use the character string "." or the threadMain constant.
No event can be sent to the current thread.

Remarks

Synchronizing threads

ThreadWaitSignal and ThreadSendSignal are used to synchronize the threads two by two. To synchronize several threads on the same event, the event functions must be used:

EventCreate: Creates an event.
EventWait: Locks the current thread and waits for the event.
EventChange: Modifies the status of an event.
EventDestroy: Destroys an event.

Note: Internal queue and stack management mechanisms eliminate the need for thread synchronization (functions Enqueue and Dequeue for queues, functions Push and Pop for stacks).

Business / UI classification: Neutral code

Component: wd300vm.dll